1 /* libunwind - a platform-independent unwind library
2 Copyright (c) 2003-2005 Hewlett-Packard Development Company, L.P.
3 Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
5 This file is part of libunwind.
7 Permission is hereby granted, free of charge, to any person obtaining
8 a copy of this software and associated documentation files (the
9 "Software"), to deal in the Software without restriction, including
10 without limitation the rights to use, copy, modify, merge, publish,
11 distribute, sublicense, and/or sell copies of the Software, and to
12 permit persons to whom the Software is furnished to do so, subject to
13 the following conditions:
15 The above copyright notice and this permission notice shall be
16 included in all copies or substantial portions of the Software.
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
29 is_cie_id (unw_word_t val, int is_debug_frame)
31 /* The CIE ID is normally 0xffffffff (for 32-bit ELF) or
32 0xffffffffffffffff (for 64-bit ELF). However, .eh_frame
35 return (val == (uint32_t)(-1) || val == (uint64_t)(-1));
40 /* Note: we don't need to keep track of more than the first four
41 characters of the augmentation string, because we (a) ignore any
42 augmentation string contents once we find an unrecognized character
43 and (b) those characters that we do recognize, can't be
46 parse_cie (unw_addr_space_t as, unw_accessors_t *a, unw_word_t addr,
47 const unw_proc_info_t *pi, struct dwarf_cie_info *dci,
48 int is_debug_frame, void *arg)
50 uint8_t version, ch, augstr[5], fde_encoding, handler_encoding;
51 unw_word_t len, cie_end_addr, aug_size;
57 # define STR(x) STR2(x)
59 /* Pick appropriate default for FDE-encoding. DWARF spec says
60 start-IP (initial_location) and the code-size (address_range) are
61 "address-unit sized constants". The `R' augmentation can be used
62 to override this, but by default, we pick an address-sized unit
64 switch (dwarf_addr_size (as))
66 case 4: fde_encoding = DW_EH_PE_udata4; break;
67 case 8: fde_encoding = DW_EH_PE_udata8; break;
68 default: fde_encoding = DW_EH_PE_omit; break;
71 dci->lsda_encoding = DW_EH_PE_omit;
74 if ((ret = dwarf_readu32 (as, a, &addr, &u32val, arg)) < 0)
77 if (u32val != 0xffffffff)
79 /* the CIE is in the 32-bit DWARF format */
81 /* DWARF says CIE id should be 0xffffffff, but in .eh_frame, it's 0 */
82 const uint32_t expected_id = (is_debug_frame) ? 0xffffffff : 0;
85 cie_end_addr = addr + len;
86 if ((ret = dwarf_readu32 (as, a, &addr, &cie_id, arg)) < 0)
88 if (cie_id != expected_id)
90 Debug (1, "Unexpected CIE id %x\n", cie_id);
96 /* the CIE is in the 64-bit DWARF format */
98 /* DWARF says CIE id should be 0xffffffffffffffff, but in
100 const uint64_t expected_id = (is_debug_frame) ? 0xffffffffffffffffull : 0;
102 if ((ret = dwarf_readu64 (as, a, &addr, &u64val, arg)) < 0)
105 cie_end_addr = addr + len;
106 if ((ret = dwarf_readu64 (as, a, &addr, &cie_id, arg)) < 0)
108 if (cie_id != expected_id)
110 Debug (1, "Unexpected CIE id %llx\n", (long long) cie_id);
114 dci->cie_instr_end = cie_end_addr;
116 if ((ret = dwarf_readu8 (as, a, &addr, &version, arg)) < 0)
119 /* GCC emits version 1??? */
120 if (version != 1 && (version < DWARF_CIE_VERSION || version > DWARF_CIE_VERSION_MAX))
122 Debug (1, "Got CIE version %u, expected version 1 or between "
123 STR (DWARF_CIE_VERSION) " and " STR (DWARF_CIE_VERSION_MAX) "\n", version);
124 return -UNW_EBADVERSION;
127 /* read and parse the augmentation string: */
128 memset (augstr, 0, sizeof (augstr));
131 if ((ret = dwarf_readu8 (as, a, &addr, &ch, arg)) < 0)
135 break; /* end of augmentation string */
137 if (i < sizeof (augstr) - 1)
141 if ((ret = dwarf_read_uleb128 (as, a, &addr, &dci->code_align, arg)) < 0
142 || (ret = dwarf_read_sleb128 (as, a, &addr, &dci->data_align, arg)) < 0)
145 /* Read the return-address column either as a u8 or as a uleb128. */
148 if ((ret = dwarf_readu8 (as, a, &addr, &ch, arg)) < 0)
150 dci->ret_addr_column = ch;
152 else if ((ret = dwarf_read_uleb128 (as, a, &addr, &dci->ret_addr_column,
157 if (augstr[0] == 'z')
159 dci->sized_augmentation = 1;
160 if ((ret = dwarf_read_uleb128 (as, a, &addr, &aug_size, arg)) < 0)
165 for (; i < sizeof (augstr) && augstr[i]; ++i)
169 /* read the LSDA pointer-encoding format. */
170 if ((ret = dwarf_readu8 (as, a, &addr, &ch, arg)) < 0)
172 dci->lsda_encoding = ch;
176 /* read the FDE pointer-encoding format. */
177 if ((ret = dwarf_readu8 (as, a, &addr, &fde_encoding, arg)) < 0)
182 /* read the personality-routine pointer-encoding format. */
183 if ((ret = dwarf_readu8 (as, a, &addr, &handler_encoding, arg)) < 0)
185 if ((ret = dwarf_read_encoded_pointer (as, a, &addr, handler_encoding,
186 pi, &dci->handler, arg)) < 0)
191 /* This is a signal frame. */
192 dci->signal_frame = 1;
194 /* Temporarily set it to one so dwarf_parse_fde() knows that
195 it should fetch the actual ABI/TAG pair from the FDE. */
196 dci->have_abi_marker = 1;
200 Debug (1, "Unexpected augmentation string `%s'\n", augstr);
201 if (dci->sized_augmentation)
202 /* If we have the size of the augmentation body, we can skip
203 over the parts that we don't understand, so we're OK. */
209 dci->fde_encoding = fde_encoding;
210 dci->cie_instr_start = addr;
211 Debug (15, "CIE parsed OK, augmentation = \"%s\", handler=0x%lx\n",
212 augstr, (long) dci->handler);
216 /* Extract proc-info from the FDE starting at adress ADDR.
218 Pass BASE as zero for eh_frame behaviour, or a pointer to
219 debug_frame base for debug_frame behaviour. */
222 dwarf_extract_proc_info_from_fde (unw_addr_space_t as, unw_accessors_t *a,
223 unw_word_t *addrp, unw_proc_info_t *pi,
225 int need_unwind_info, int is_debug_frame,
228 unw_word_t fde_end_addr, cie_addr, cie_offset_addr, aug_end_addr = 0;
229 unw_word_t start_ip, ip_range, aug_size, addr = *addrp;
230 int ret, ip_range_encoding;
231 struct dwarf_cie_info dci;
235 Debug (12, "FDE @ 0x%lx\n", (long) addr);
237 memset (&dci, 0, sizeof (dci));
239 if ((ret = dwarf_readu32 (as, a, &addr, &u32val, arg)) < 0)
242 if (u32val != 0xffffffff)
244 int32_t cie_offset = 0;
246 /* In some configurations, an FDE with a 0 length indicates the
247 end of the FDE-table. */
251 /* the FDE is in the 32-bit DWARF format */
253 *addrp = fde_end_addr = addr + u32val;
254 cie_offset_addr = addr;
256 if ((ret = dwarf_reads32 (as, a, &addr, &cie_offset, arg)) < 0)
259 if (is_cie_id (cie_offset, is_debug_frame))
260 /* ignore CIEs (happens during linear searches) */
264 cie_addr = base + cie_offset;
266 /* DWARF says that the CIE_pointer in the FDE is a
267 .debug_frame-relative offset, but the GCC-generated .eh_frame
268 sections instead store a "pcrelative" offset, which is just
269 as fine as it's self-contained. */
270 cie_addr = cie_offset_addr - cie_offset;
274 int64_t cie_offset = 0;
276 /* the FDE is in the 64-bit DWARF format */
278 if ((ret = dwarf_readu64 (as, a, &addr, &u64val, arg)) < 0)
281 *addrp = fde_end_addr = addr + u64val;
282 cie_offset_addr = addr;
284 if ((ret = dwarf_reads64 (as, a, &addr, &cie_offset, arg)) < 0)
287 if (is_cie_id (cie_offset, is_debug_frame))
288 /* ignore CIEs (happens during linear searches) */
292 cie_addr = base + cie_offset;
294 /* DWARF says that the CIE_pointer in the FDE is a
295 .debug_frame-relative offset, but the GCC-generated .eh_frame
296 sections instead store a "pcrelative" offset, which is just
297 as fine as it's self-contained. */
298 cie_addr = (unw_word_t) ((uint64_t) cie_offset_addr - cie_offset);
301 Debug (15, "looking for CIE at address %lx\n", (long) cie_addr);
303 if ((ret = parse_cie (as, a, cie_addr, pi, &dci, is_debug_frame, arg)) < 0)
306 /* IP-range has same encoding as FDE pointers, except that it's
307 always an absolute value: */
308 ip_range_encoding = dci.fde_encoding & DW_EH_PE_FORMAT_MASK;
310 if ((ret = dwarf_read_encoded_pointer (as, a, &addr, dci.fde_encoding,
311 pi, &start_ip, arg)) < 0
312 || (ret = dwarf_read_encoded_pointer (as, a, &addr, ip_range_encoding,
313 pi, &ip_range, arg)) < 0)
315 pi->start_ip = start_ip;
316 pi->end_ip = start_ip + ip_range;
317 pi->handler = dci.handler;
319 if (dci.sized_augmentation)
321 if ((ret = dwarf_read_uleb128 (as, a, &addr, &aug_size, arg)) < 0)
323 aug_end_addr = addr + aug_size;
326 if ((ret = dwarf_read_encoded_pointer (as, a, &addr, dci.lsda_encoding,
327 pi, &pi->lsda, arg)) < 0)
330 Debug (15, "FDE covers IP 0x%lx-0x%lx, LSDA=0x%lx\n",
331 (long) pi->start_ip, (long) pi->end_ip, (long) pi->lsda);
333 if (need_unwind_info)
335 pi->format = UNW_INFO_FORMAT_TABLE;
336 pi->unwind_info_size = sizeof (dci);
337 pi->unwind_info = mempool_alloc (&dwarf_cie_info_pool);
338 if (!pi->unwind_info)
341 if (dci.have_abi_marker)
343 if ((ret = dwarf_readu16 (as, a, &addr, &dci.abi, arg)) < 0
344 || (ret = dwarf_readu16 (as, a, &addr, &dci.tag, arg)) < 0)
346 Debug (13, "Found ABI marker = (abi=%u, tag=%u)\n",
350 if (dci.sized_augmentation)
351 dci.fde_instr_start = aug_end_addr;
353 dci.fde_instr_start = addr;
354 dci.fde_instr_end = fde_end_addr;
356 memcpy (pi->unwind_info, &dci, sizeof (dci));